3-Methylglutamic acid

Fig. 10. Stmcture of daptomycin where L-Kyn is L-kynurenine and (h-threo) 3-MeGlu is L-// fi (9-3-methylglutamic acid.

Gruszecka, E., Soroka, M., and Mastalerz, P, Phosphonic analogs of a-meth-ylaspartic and a-methylglutamic acids, Pol.. Chem., 53, 2327, 1979. 

Other Oxazolidine as well as Thiazolidine Derivatives for Branching Amino Acids. The cyclic derivative of alanine and other amino acids employed most frequently for a-allq lation is not (1) but rather the benzaldehyde acetal (5), either with a benzoyl or with a Cbz group on nitrogen. These compounds were used for the preparation of 2-methyl-2-aminobutanoic acid, a-methylphenylalanine, a-methyllysine, 2-methylaspartic acid, and 2-methylglutamic acid. Bicyclic compounds containing oxazolidinone rings such as (6) (from alanine, leucine, and phenylalanine) and (7) (from azetidinecaiboxylic acid, proline, " hydroxyproline, and cysteine ) have also been applied to the synthesis of branched amino acids. 

Other substances to which people have been exposed have been shown to alter the toxic effects of ammonia. Methionine sulfoximine, administered by intraperitoneal injection, suppressed the tonic convulsions produced by intravenous injection of ammonium chloride in mice (Hindfelt and Plum 1975 Warren and Schenker 1964). Intraperitoneal injection of alpha-methylglutamic acid also exerts a protective effect against hyperammonemia in rats (Lamar 1970). Nicotinohydroxamic acid and neomycin administered orally reduce blood ammonia levels and increase excretion of urea in treated rats (Haiada et al. 1985). Ethanol exerted a protective effect on acute ammonia intoxication in mice (O Connor et al. 

Lamar C. 1970. Ammonia toxicity in rats Protection by a -methylglutamic acid. Toxicol Appl Pharmacol 17 795-803. 

The enolatc of (2S,4R)-I can also undergo Michael addition to f-butyl acrylate. The yield is low, but the adduct is obtained in 98% ee. This reaction provides a route to a derivative of 2-methylglutamic acid (equation I). 

In spite of their potential in synthesis, accounts of additions of hydrophosphoryl compounds to enamines are spread rather thinly throughout the literature. As a contribution towards the synthesis of methylaspartic acid and methylglutamic acid analogues, ethyl esters of phosphinic acids, (EtO)RP(0)H, were shown to add to ethyl 3-aminobut-2-... 

An example of the third type (novel pathway) is the production of ery A o-4-methylglutamic acid (9) from L-leucine (10) in Gleditisia triacanthos (honey locust, Fabaceae) and not from glutamic acid and SAM or from lysine as in many other plants (Fig. 13.4). 

Ring openings interrelate cis-3- and cw-4-methylated pro-line (30, 31) as well as pipecolic acid (17) into these metabolic pathways. Addition of water to baikiain (28) can lead to trans-4- and/or rm j-5-hydroxypipecolic acid (32, 33). 4-Methylglutamic acid (9) can feed into cij-4-methylproline (31), 4-methyleneglutamic acid (26) into 4-methylenepro-... 

Methylglutamic acid (9), (25, 45)-4-hydroxy-4-meth-ylglutamic acid (70) and 4-methyleneglutamic acid (26) apparently are derived from leucine (Fig. 13.14) (Rosenthal, 1982). All these compounds are found in honey locust, Gleditsia triacanthos (Fabaceae). 4-Methyleneglutamic acid (26) is also stored in the peanut, Arachis hypogaea (Fabaceae). 

Numerous other substituted glutamic acids are found in plants (37), whereas the structurally corresponding amides have not been detected. The glutamine synthetase isolated from peas was, however, able to catalyze the synthesis of 4-methylglutamine from 4-methylglutamic acid (196). 

---